Method of preventing double bond migration of mono-olefinic hydrocarbons in selective hydrogenation

ABSTRACT

METHOD OF PREVENTING DOUBLE BOND MIGRATION OF A MONOOLEFINIC HYDROCARBON DURING THE SELECTIVE HYDROGENATION OF A POLY-UNSATURAED HYDROCARBON (E.G. POLYOLEFINIC HYDROCARBON, ACETYLENIC HYDROCARBON) COEXISTING WITH A MONOOLEFINIC HYDROCARBON, EACH OF THE MONO-OLEFINIC HYDROCARBONS AND POLY-UNSATURATED HYDROCARBONS HAVING AT LEAST FOUR CARBON ATOMS, IN THE PRESENCE OF HYDROGEN, USING A PALLADIUM- OR NICKEL-HYDROGENATION CATALYST, WHICH COMPRISES ADDING CARBON MONOXIDE TO THE REACTION SYSTEM IN AN AMOUNT 1 TO 50 MOL. PERCENT BASED ON SAID HYDROGEN UNDER SELECTIVELY HYDROGENATION CONDITIONS.

May 9, 1972 YQUJI'KQMATSU E'I'AL 3,662,015

METHOD OF PREVENTING DOUBLE BOND MIGRATION 0F MONO-OLEEINIC HYDROCARBONS IN SELECTIVE HYDROGENATION Filed May 27, 1969 HGI (p.p.m) 20,000

United States Patent 3,662,015 METHOD OF PREVENTING DOUBLE BOND MIGRATION 0F MONO-OLEFINIC HYDRO- CARBONS IN SELECTIVE HYDRUGENATION Youji Komatsu, llchihara-shi, Yasuhiro Furukawa, Funabashi-shi, and Takashi Yokomizo, llchihara-slii, .l apan, assignors to Marnzen Oil Company, Ltd, Osaka, Japan Filed May 27, 1969, Ser. No. 828,186 Claims priority, application Japan, May 27, 1968, 43/ 35,522 Int. Cl. C07c /16 US. Cl. 260-677 H 14 Claims ABSTRACT OF THE DISCLOSURE Method of preventing double bond migration of a monoolefinic hydrocarbon during the selective hydrogenation of a poly-unsaturated hydrocarbon (e.g. polyolefinic hydrocarbon, acetylenic hydrocarbon) coexisting with a mono olefinic hydrocarbon, each of the mono-olefinic hydrocarbons and poly-unsaturated hydrocarbons having at least four carbon atoms, in the presence of hydrogen, using a palladiumor nickel-hydrogenation catalyst, which comprises adding carbon monoxide to the reaction system in an amount 1 to 50 mol. percent based on said hydrogen under selective hydrogenation conditions.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a method of preventing the double bond migration of mono-olefinic hydrocarbons during the selective hydrogenation of poly-unsaturated hydrocarbons of poly-olefinic and/ or acetylenic types coexisting with said mono-olefinic hydrocarbons, each of the mono-olefinic hydrocarbons and the poly-unsaturated hydrocarbons having at least four carbon atoms.

Description of the prior art It is generally known that a poly-unsaturated hydrocarbon of the poly-olefinic and/or acetylenic type having at least four carbon atoms, coexisting with a mono-olefinc hydrocarbon having at least four carbon atoms, may be hydrogenated in the presence of hydrogen using a hydrogenation catalyst such as palladium-, platiniumor nickel, to selectively convert said poly-unsaturated hydrocarbons into the corresponding mono-olefinic hydrocarbons. Such a process is hereinafter referred to as selective hydrogenation. For example, it is widely known and industrially employed that butene containing C -diolefins and/or C -acetylenes may be selectively hydrogenated in the presence of hydrogen using a palladium, platinum or nickel catalyst to convert said C -dio1efins and/or C acetylenes into the corresponding butenes, without loss of butenes, thereby obtaining butenes substantially free from said C -diolefins and C -acetylenes.

However, the conventional hydrogenation catalysts, such as palladium, platinum and nickel, used for such selective hydrogenation processes possess the disadvantage of promoting double bond migration in addition to the desired hydrogenation of the unsaturated bonds, Accordingly, conventionally practiced selective hydrogenations employing such catalysts are inevitably accompanied by double bond migration of mono-olefinic hydrocarbons.

For example, the selective hydrogenation of butenes (e.g. l-butene, Z-butene, isobutene) containing C -diolefins (e.g. 1,3-butadiene, methyl allene) and/or C -acetylenes (e.g. dimethyl acetylene, ethyl acetylene, vinyl acetylene) in conventional process as involves both the selective hydrogenation reaction of C -diolefins and/or C acetylenes into butenes and the double bond migration of ice l-butene into Z-butene. As a result, the greater part of the l-butene is lost. This problem becomes very serious when it is desired to selectively hydrogenate l-butene containing C -diolefins and/or c -acetylenes to obtain pure l-butene or a fraction rich in l-butene, free from C -diolefins and C -acety1enes, l-butene and l-butene-rich fractions are useful chemical feed materials for the production of poly-l-butene, l-butene copolymer, etc.

It has, accordingly, been long desired in this art to develop a method of preventing the double bond migration of mono-olefinic hydrocarbons effectively during the selective hydrogenation of poly-unsaturated hydrocarbons coexisting with mono-olefinic hydrocarbons.

However, no effective process has yet been proposed despite expensive and elaborate studies which have been performed to date.

SUMMARY OF THE INVENTION We have found that double bond migration in monoolefinic hydrocarbons can be effectively prevented during the selective hydrogenation of polyunsaturated hydrocarbons coexisting with said mono-olefinic hydrocarbons, each of the mono-olefinic and poly-unsaturated hydrocarbons having at least four carbon atoms, by carrying out the reaction in the presence of hydrogen, a palladium or nickelhydrogenation catalyst and 1-50 mol. percent, preferably 530 mol. percent, of carbon monoxide, based on said hydrogen.

Accordingly, the basic object of the present invention is to provide a method of preventing the double bond migration of mono-olefinic hydrocarbons during the selective hydrogenation of poly-unsaturated hydrocarbons coexisting with mono-olefinic hydrocarbons, each of mono-olefinic hydrocarbons and poly-unsaturated hydrocarbons having at least four carbon atoms, in the presence of hydrogen using a palladium or nickel-hydrogenation catalyst.

Another object of the present invention is to provide a process for the selective hydrogenation of poly-unsaturated hydrocarbons containing mono-olefinic hydrocarbons, each of said poly-unsaturated hydrocarbons and mono-olefinic hydrocarbons having at least four carbon atoms, in the absence of the usual accompanying double bond migration.

Still another object of the present invention is to provide a method of inhibiting only the isomerization (double bond migration) activity of conventional hydrogenation catalysts being employed for the selective hydrogenation of poly-unsaturated hydrocarbons coexisting with monoolefinic hydrocarbons, each of said poly-unsaturated hydrocarbons and mono-olefinic hydrocarbons having at least four carbon atoms.

These and other objects of the present invention will become apparent from the following detailed description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2, 3 and 4 indicate the changes in the composition of the hydrogenation products with reference to 1,3-butadiene and l-butene, obtained by the selective hydrogenation of butenes containing 1,3-butadiene using a palladium hydrogenation catalyst at a temperature of C., a pressure of 25 kg./cm. and a hydrogen atmosphere containing 0, 10, 25 and 50 mol. percent of carbon monoxide respectively, based on the hydrogen present. All tests in FIGS. 1-4 are carried out under the same reaction conditions, e.g., feed stocks, hydrogenation catalyst employed, reaction temperature and total pressure etc., except that the content of carbon monoxide in the hydrogen is varied respectively. In each figure, the right axis of ordinate indicates the content of 1,3-butadiene (p.p.m.), the left axis of ordinate indicates the content of l-butene (mol. percent) and the axis of abscissa indicates the reaction period (in hours). The solid line of each figure indicates the change in l-butene content and the dotted line indicates the change in 1,3-butadiene content.

DETAILED DESCRIPTION OF THE INVENTION According to the process of this invention, the poly unsaturated hydrocarbons coexisting with the monoolefinic hydrocarbons, each of which hydrocarbons having at least four carbon atoms, are selectively hydrogenated in the presence of hydrogen and 150 mol. percent of carbon monoxide, based on the hydrogen, using a palladium or nickel catalyst. As a result, said polyunsaturated hydrocarbons are selectively hydrogenated and thus eliminated, and the double bond migration of said mono-olefinic hydrocarbons is effectively prevented.

A clear understanding of the invention may be had by reference to the drawings, and the following description and examples of the invention.

As is apparent from FIGS. 1, 2, 3 and 4, conventional selective hydrogenation, in which butene containing 1,3- butadiene is selectively hydrogenated in the presence of hydrogen alone, although effectively eliminating the 1,3- butadiene, also results in the substantial disappearance of l-butene by the double bond migration of l-butene into Z-butene (cf. FIG. 1). On the other hand, selective hydrogenation according to the present invention, in which the same butene containing 1,3-butadiene is selectively hydrogenated in the presence of a specific amount of carbon monoxide, also effectively eliminates the 1,3-butadiene, but the reaction product is almost unchanged l-butene content, owing to the effective prevention of double bond migration. (cf. FIGS. 2, 3 and 4).

In accordance with the present invention, it is possible to effectively prevent the double bond migration, not only in the selective hydrogenation of butenes containing 1,3- butadiene, but also in the selective hydrogenation of other higher mono-olefinic hydrocarbons containing C or higher poly-unsaturated hydrocarbons, by adding carbon monoxide to the selective hydrogenation system.

It is a surprising and unpredictable discovery that carbon monoxide effectively prevents the double bond migration in selective hydrogenation processes employing conventional hydrogenation catalysts, such as palladiumand nickel catalyst.

It has been suggested, with regard to the selective hydrogenation of ethylene/acetylene mixtures, to carry out the reaction in the presence of carbon monoxide or a sulfur compound (for example hydrogen sulfide, mercaptans, carbon disufide) as a means of increasing the selectivity of the hydrogenation catalyst, i.e. for the purpose of facilitating the hydrogenation of acetylene selectively into ethylene Without excessive hydrogenation of ethylene into ethane. However, it has not heretofore been suggested that carbon monoxide would be useful to prevent double bond migration of mono-olefinic hydrocarbons containing 4 or more carbon atoms. Accordingly, the use of carbon monoxide in present invention is basically different from such prior art use, actually and conceptually. Moreover, in the case of ethylene/acetylene mixtures, either carbon monoxide or sulfur compounds are effective to increase the selectivity of the hydrogenation catalyst towards the hydrogenation of acetylene. On the other hand, the ability to prevent double bond migration in the process of the present invention is possessed only by carbon monoxide, and not by sulfur compounds. Double bond migration in compounds having four or more carbon atoms cannot be prevented by the use of sulfur compounds, it being the peculiar property of carbon monoxide to prevent such migration in the selective hydrogenation process of the present invention.

'A hydrocarbon feed utilized in the selective hydrogenation of the present invention comprises a mixture of mono-olefinic hydrocarbon and a poly-unsaturated hydrocarbon, each having at least four carbon atoms. Practically speaking, the hydrocarbon feed may contain hydrocarbons having up to 16 carbon atoms. The said polyunsaturated hydrocarbons are poly-olefinic hydrocarbons (e.g. di-olefins, tri-olefin's and the like) and/ or acetylenic hydrocarbon (e.g. alkynes, alkenynes). The content of the poly-unsaturated hydrocarbons in the hydrocarbon feed are preferably less than about 50 mol. percent. Feeds containing greater amounts of poly-unsaturated hydrocarbons may, however, be employed within the scope of the invention. In addition, the hydrocarbon feed may contain parafiinic hydrocarbons, such as n-butane, pentane, hexane, etc., and inert gases, such as hydrogen, nitrogen, etc.

Hydrogen to be used in this invention may be either pure hydrogen or hydrogen-containing gases, such as natural gas, Platformer elf-gas, etc.

If the hydrocarbon feed already contains hydrogen, the rest of hydrogen being required for the selective hydrogenation of this invention may be supplied from an external source. The amount of hydrogen employed in the present invention will vary depending upon the contents of the poly-unsaturated hydrocarbon in the hydrocarbon feed. It is necessary to use more than the stoichiometric amount of hydrogen needed for hydrogenating the polyunsaturated hydrocarbons into corresponding mono-olefinic hydrocarbons. In general, 1-20,000 moles of hydrogen per total mole of poly-unsaturated hydrocarbons may be employed for the selective hydrogenation.

:The hydrogenation catalyst to be used in the present invention is a hydrogenation catalyst containing palladiurn or nickel. Suitable hydrogenation catalysts are palladium or nickel metals, or the sulfides or oxides of these metals, or such metals or compounds supported on known carriers, such as alumina, silica-alumina, magnesia, titania, diatomaceous earth etc. by conventional treatment. Preferable catalysts are palladium-supported on carrier (Pd cont.=0.0053 weight percent or nickel on a supported carrier (Ni cont.=1-40 Weight percent).

In accordance with the present invention, the selective hydrogenation of poly-unsaturated hydrocarbons coexisting with mono-olefinic hydrocarbons, wherein each of the poly-unsaturated and mono-olefinic hydrocarbons has at least four carbon atoms is easily carried out, without causing double bond migration in the mono-olefinic hydrocarbons, in the presence of hydrogen as aforesaid and 1-50 moi percent preferably 5-3O mole percent, of carbon monoxide, based on the hydrogen present, using a palladiumor nickel catalyst. The use of carbon monoxide in an amount of less than 1 mol percent based on the hydrogen present is not desirable, since double bond migration will take place along with the selective hydrogenation. If the amount of carbon monoxide is more than 50 mole percent, other disadvantages become apparent, e.g. prolongation of the reaction period for the selective hydrogenation, of the polyunsaturated hydrocarbon take place, although the double bond migration is still prevented.

The carbon monoxide may be introduced to the reaction system in any manner as long as hydrogen is also present. In practical operation, it is convenient to previously mix the carbon monoxide with hydrogen in a specific ratio and then to bring the resultant carbon monoxide-hydrogen mixture into contact with the hydrocarbon feed.

The selective hydrogenation of the present invention is preferably carried out at a tempearture of 20-250 C. under the pressure of about atmospheric to 50 kg./crn. Under such a relatively mild reaction condition, skeletal isomerization of the mono-olefinic hydrocarbons will not take place in any substantial amount during the selective hydrogenation. The hydrocarbon feed is introduced as either an upflow or downfiow to a reactor packed with the hydrogenation catalyst at an L.H.S.V. of 0.1-40 and is selectively hydrogenated therein. Although it is convenient to contact the hydrocarbon feed with the hydrogenation catalyst in a fixed bed, if necessary or desired, a moving or fluidized bed may be employed. The selective hydrogenation may be carried out either in batch, semicontinuous or continuous operation. It is also possible to introduce a sulfur compound, such as hydrogen sulfide, mercaptan or carbon disulfide together with carbon monoxide to the reaction system for the purpose, of avoiding excessive hydrogenation in the process of this invention.

According to the process of this invention, it has now become possible to effectively prevent double bond migration in mono-olefinic hydrocarbons which has always accompanied conventional selective hydrogenation of mixtures of mono-olefinic and poly-unsaturated hydrocarbons having at least four carbon atoms. The process of this invention therefore has wide industrial applications not only as a process for selective hydrogenation in the absence of double bond migration but also in process as directed to the production of a particular hydrocarbon which may be altered in conventional selective hydrogenation by double bond migration.

The present invention is particularly useful in carrying out the selective hydrogenation of butenes containing C diolefins and/or C -acetylenes without lowering the 1- butene content, and also in obtaining l-butene, or a fraction rich in l-butene, from l-butene mixtures with C -diolefins and/or C acetylenes by selective hydrogenation. However, the field of the application of the present invention is not limited only to those specific examples.

The following examples are illustrative, but not limiting, of the invention.

EXAMPLE 1 The hydrocarbon feed employed was a butene-containing feed having the composition shown in Table 1. Said butene feed is a raflinate extracted from a C -fraction produced by naphtha steam cracking.

The hydrogenation catalyst employed was a commercial palladium catalyst (PGCC produced by Engelhard Industries, Ltd.) containing 0.1% by weight of palladium supported on alumina.

A vertically disposed reactor of 50 mm inner diameter was packed with 200 ml. of the palladium catalyst. Into the reactor, there were continuously introduced the butene feed mixed with p.p.m. of hydrogen sulfide at the rate of 600 mL/hr. (L.H.S.V=3.0) and hydrogen containing 25 mol. percent carbon monoxide at the rate of 60 liters (N. T.P.)/hr. at a temperature of 100 0., under a pressure of 25 kg./cm. to effect the selective hydrogenation. A hydrogenation product thus obtained was analyzed by gas chromatography. The composition of the As is apparent from the Table 1, 1,3-butadiene had completely disappeared in the product owing to the selective hydrogenation, but the content of l-butene remains unchanged. This clearly proves that double bond migration during selective hydrogenation is eifectively prevented.

EXAMPLE 1a The selective hydrogenation was carried out using the same feed, catalyst and reaction conditions as those used in Example 1 except that hydrogen free from carbon monoxide was utilized. The compositions of the butene feed and the hydrogenation product are given in Table 2.

TAB LE 2 Feed Product composition composition (mol percent) (mol percent) Propane and propylene 2. 6 2. 6 Isobutane 3. 6 6. 1 9 6 13.3 43.0 43. 1 25. 9 4. 0 14. 1 31. 4 1. 2 0.05

As is apparent from the Table 2, almost all of l-butene undergoes double bond migration and is converted to 2- butene during selective hydrogenation if carbon monoxide is not present in the reaction system.

EXAMPLE 2 The procedure of Example 1 was carried out except that a nickel-containing hydrogenation catalyst containing 10% by weight of nickel supported on alumina was used in place of the palladium-alumina catalyst. The said nickel catalyst was prepared by the following procedure: A solution was prepared by dissolving nickel nitrate 170 g. in water 170 g.: An alumina pellet (5 x 5 mm.) 300 g. was then impregnated with the nickel nitrate solution. The impregnated alumina pellet was dried to evaporate Water. The pellet was calcined in the air at 400 C. for 5 hours and then at 650 C. for 4 hours. The calcined catalyst was reduced with hydrogen at 400 C. for 4 hours. The compositions of the butene feed and the hydrogenation product are given in Table 3.

TABLE 3 Feed Product composition composition (mol percent) (mol percent) Propane and propylene 2. 6 2. 7 Isobutane- 3. 6 3. 7 n-Butane. 9. 6 9. 9 Isobutene. 43. 0 43. 0 l-butene 25. 9 25. 3 2-butene l4. 1 15. 4 1,3-butadiene 1. 2 0

EXAMPLE 3 The procedure of Example 1 was carried out except that the hydrocarbon feed employed was a 0.; fraction having the composition shown in Table 4, which was produced by naphtha steam cracking, and that the rate of hydrogen containing 25 mol. percent carbon monoxide was 600 liters (N.T.P.)/hr.

The composition of the feed and the product obtained are given in Table 4.

EXAMPLE 4 The procedure of Example 1 was carried out except that the hydrocarbon feed employed was a C -fraction, and that the rate of hydrogen containing 13 mol percent carbon monoxide was liters (N.T.P.)/hr. The composition of the feed and product are given in Table 5.

EXAMPLE 5 The procedure of Example 1 was carried out except that the hydrocarbon feed employed was an octene feed containing methyl heptatriene, and that the rate of hydro gen containing 13 mol percent carbon monoxide was 300 liters (N.T.P.)/hr.

The composition of the feed and product are given in Table 6.

TABLE 6 Feed Product composition composition (mol percent) (mol percent) l-octene 68. 67.8 z-octene 3. 4 3. 9 B-methyl heptatriene- 26. 0 0. 3 3-methyl heptadiene 0 22. 5 3 metl1yl heptene 0 2.1 Others 2 6 3. 7

As is apparent from Table 6, 3-methyl heptatriene is selectively hydrogenated into 3-methyl heptadiene and then successively into 3-methyl heptene, but the product content of l-octene shows little change from that of the feed. According to the process of this invention, higher polyolefin than C tri-olefins can be selectively hydrogenated as well with effective prevention of the double bond migration.

What is claimed is:

1. A method for preventing the double bond migration of a mono-olefin having at least four carbon atoms during the selective hydrogenation of a hydrocarbon mixture containing at least one of said mono-olefin and at least one polyunsaturated hydrocarbon having at least four carbon atoms, selected from the group consisting of a polyolefin, an alkyne, an alkenyne, and mixtures thereof, in the presence of hydrogen and a hydrogenation catalyst, which comprises:

passing said hydrocarbon mixture in the liquid phase at a liquid hourly spaced velocity ranging from 0.1 to 40 over said hydrogenation catalyst, said catalyst consisting of a carrier and a member selected from the group consisting of palladium and nickel in the presence of from 1 to 50 mol percent of carbon monoxide, based upon the amount of hydrogen present.

2. The process of claim 1 wherein the carbon monoxide is present in an amount of from 5 to 30 mol percent, based on said hydrogen.

3. The process of claim 1 wherein the hydrocarbon mixture is a C fraction.

4. The process of claim 1 wherein the hydrocarbon mixture is a mixture of compounds having from 4 to 16 carbon atoms in the molecule.

5. The process of claim 1 wherein the hydrocarbon mixture is a C fraction.

6. The process of claim 1 wherein the hydrocarbon mixture is a C fraction.

7. The process of claim 1 wherein the hydrocarbon mixture contains paraffinic hydrocarbons.

8. The process of claim 1 wherein the hydrogenation is carried out in the presence of 1 to 20,000 moles of hydrogen per total mole of polyolefin, alkyne and alkenyne in the reaction mixture, at a temperature of about 20 to 250 C. and a pressure of about atmospheric to 50 kg./ cm.

9. The process of claim 1, wherein the palladium catalyst is present in an amount of from 0.005 to 3.0 percent by weight, and the carrier is present in an amount of at least 97.0 percent by weight.

10. The process of claim 1, wherein the nickel catalyst is present in an amount of from 1.0 to 40.0 percent by weight, and the carrier is present in an amount of at least 60.0 percent by weight.

11. The process of claim 1, wherein the carrier is a member selected from the group consisting of alumina, silica-alumina, magnesia, titania, and diatomaceous earth.

12. The process of claim 1, wherein the carrier is alumma.

13. The process of claim 1, wherein an amount of a sulfur compound effective for avoiding excess hydrogenation of the mono-olefins is added together with the carbon monoxide introduced into the reaction system.

14. The process of claim 13, wherein said sulfur compound is a member selected from the group consisting of hydrogen sulfide, mercaptan and carbon disulfide.

References Cited UNITED STATES PATENTS 2,775,634 12/1956 Nowlin 260-677 3,325,556 6/1967 De Rosset 260-677 3,404,101 10/1968 Weisang ct al 260-677 X 3,481,999 12/1969 Reich 260-677 PAUL M. COUGHLAN, I 11., Primary Examiner US. Cl. X.R. 260-680 R 

